Gasket for cladding system

ABSTRACT

A method of forming a joint ( 32 ) between two plastics extrusions ( 10 ) is disclosed which comprises mitring the extrusions ( 10 ) so that they form the desired angle to one another removing part of the rear face of each extrusion ( 10 ) placing the mitred extrusions in a mould and injecting a resin material whereby to bond the extrusions ( 10 ) to one another and produce the desired joint ( 32 ) configuration. Because the front surface ( 24 ) of the joint in accordance with the invention is entirely made up from the original extrusion, there are no problems with raised sight-lines, colour differentials, surface differences, or colour matching. Moreover, the method of the invention allows a corner to be produced which has a clean right angled rather than radiused inner portion.

[0001] This invention relates to an improved method of producing agasket for a building cladding, curtain wall or glazing system, and tothe gasket so made.

[0002] The term ‘gasket’ refers to the rubber or other plastics materialextrusions used to hold or seal an infill into a framework or the likein a curtain walling/glazing system in the construction of buildings.

[0003] In our published UK patent specification number 2 023 703 and ourEuropean patent publication number 0 059 058 building systems aredescribed in which infill members are held in place on a framework bymeans of a flexible gasket which locates and is gripped by the frameworkand has a limb extending so as to bear against the infill and hold it inplace. This system is very successful and is used extensively. Aparticular feature of it, which appeals to architects, is that thegasket can be of various colours, or indeed multi-coloured, to produce adesired aesthetic effect.

[0004] One problem area in connection with the gaskets of the abovesystems is in connection with the gasket corners. Reference to FIGS. 1and 2 of the accompanying drawings illustrates the current method ofproducing corners. The main runs of the gasket are extruded to thedesired length. Two extrusions 10 are inserted into a mould 12 and ashot of silicone compound is inserted under pressure into the heatedmould forming a joint 14 between the two extrusions. Because themoulding is carried out under pressure, it is easy for protruding lines16 to appear on the resultant product, which are not aestheticallypleasing. Similarly, because the corner is injected rather thanextruded, there is very often a colour differential and a differentsurface finish between the corner 14 and the extrusions 10. In addition,the corner needs to be radiused at 18 to ensure weather-tightness when aclean right angle may be preferred aesthetically. Finally, it is onlypossible to use a single solid colour whereas the extrusions can beproduced in multiple colours or with metallic pigments.

[0005] The invention seeks to provide a method of forming a gasketjoint, e.g. corner, improved in the above respects.

[0006] According to the present invention there is provided a method offorming a joint between two plastics extrusions which comprises mitringthe extrusions so that they form the desired angle to one another,removing part of the rear face of each extrusion, placing the mitredextrusions in a mould and injecting a resin material whereby to bond theextrusions to one another and produce the desired joint configuration.

[0007] Because the front surface of the joint in accordance with theinvention is entirely made up from the original extrusion, there are noproblems with raised sight-lines, colour differentials, surfacedifferences, or colour matching. Moreover, the method of the inventionallows a corner to be produced which has a clean right angled ratherthan radiused inner portion.

[0008] The extrusions will be made from a suitable plastics materials,e.g. as described in the above mentioned patent publications. Currentlyit is preferred that the extrusions are made from a silicone rubber,although other plastics materials may be used. Accordingly the resinused to form the joint is normally also a silicone rubber mix which willcure under heat and pressure in order to produce the joint, althoughother compatible plastics materials can be used. Also, although theinvention is especially useful when used with the extrusions of ourabove referred-to patent publications, it has wider applications and canbe used to join plastics extrusions in the curtain wall/glazing fieldgenerally, wherever it is desired to maintain the surface appearance ofan extrusion through the joint or corner.

[0009] The invention further includes a gaskets having joints formed inaccordance with the above.

[0010] The invention will be described further, by way of example, withreference to the accompanying drawings, in which:

[0011]FIGS. 1 and 2 are diagrammatic illustrations of the currentmethod;

[0012]FIG. 3 is a front elevational view of a seal in accordance withthe method of the invention;

[0013]FIG. 4 is a perspective view corresponding to FIG. 3;

[0014]FIG. 5 is a partial sectional view;

[0015]FIG. 6 is a rear elevation corresponding to FIG. 3;

[0016]FIG. 7 is a rear perspective view;

[0017]FIG. 8 is a cross-sectional view of the extrusion on an enlargedscale; and

[0018]FIG. 9 shows perspective views of the extrusion from both sides.

[0019] Referring to the drawings, and firstly FIGS. 1 and 2, as has beenindicated above in the existing method of forming a corner joint twoextrusions 10 are brought together in a mould 12 and injected with asilicone material under heat and pressure to produce a joint 14. Theinner corner of the joint 14 is radiused at 18.

[0020] Referring now to FIGS. 3 to 9, in the method of the invention, bycontrast, and using like numbers for like parts, the extrusions 10 aremitred at an appropriate angle, for example 45° to produce a 90° corner(although other angles may be used for different shape infill panels).The mitred ends 20 are brought together in a butt joint 22. Theextrusions 10 have front faces 24 and rear faces 26. The latter aremoulded with indented “foot” portions 28 designed to locate in channelsin the building framework (not shown).

[0021] In the area of the joint the back of each extrusion 10 is cutaway along a line 30 at the back of the extrusions. Thus, the frontfaces 24 are left untouched.

[0022] The butt joined cut-away extrusions are then put into a mould ofthe requisite shape and injected with a suitable resin 32, e.g. asilicone, as before. The mould is shaped to continue the foot portions28 and to provide a pillar 38 if required by the system. From the front,therefore, the extrusions are unbroken and any multi-colour lines,metallic lines, or the like continue unbroken to the butt joint 22.There are no unsightly raised lines and the problems with the previousmethod of joining are overcome.

[0023] The extrusions 10 have sealing lips 40 as before which bearagainst the infill, e.g. double glazing unit, in use. In accordance withthe invention it is preferred, in addition, to provide a second sealinglip 42 on the extrusions 10 which can be continued in the area of thejoin 32. This ensures that the corner is weather-tight and obviates theneed to radius the inner corner of the join, i.e. the seal 40, allowinga “clean” 90° angle to be achieved. It is preferred to radius the innerlip 42 and have a clean right outer lip 40.

[0024] As can be seen from FIG. 8, some extrusions have differentcoloured areas 24 a and 24 b and these can be carried right through thejoint in the method of the invention.

1. A method of forming a joint between two plastics extrusions whichcomprises mitring the extrusions so that they form the desired angle toone another, removing part of the rear face of each extrusion, placingthe mitred extrusions in a mould and injecting a resin material wherebyto bond the extrusions to one another and produce the desired jointconfiguration.
 2. A method as claimed in claim 1 wherein the extrusionsare made from a silicone rubber.
 3. A method as claimed in either ofclaims 1 or 2 in which the resin used to form the joint is a siliconerubber mix which will cure under heat and pressure in order to producethe joint.
 4. A method as claimed in any of claims 1 to 3 in which jointis a corner.
 5. A method as claimed in claim 4 in which the extrusionsare at substantially 90° to one another.
 6. A method as claimed in anyof claims 1 to 5 in which the extrusions have a primary seal and inaddition there is a secondary seal on the bottom surface.
 7. A method asclaimed in claim 6 in which the primary seal is cut to form am angledjoint while the secondary seal is radiussed around the corner.
 8. Ajoint formed by the method in accordance with any preceding claim.